2-Cyanoacrylate based compositions containing a 2-cyanoacrylic acid ester can initiate polymerization due to their anionic polymerizability by slight anion such as scanty moisture adhering to adherend surfaces, and can firmly join various materials in a short time. Hence, they are used as so-called instantaneous adhesives in broad fields such as industrial, medical and household fields. Although various components such as stabilizers, curing accelerators, thickeners and plasticizers have conventionally been blended with 2-cyanoacrylate based compositions in order impart required performance, the components that can be blended therewith are limited due to the above anionic polymerizability. Hence, in order to provide a joining portion with magnetism, it was necessary to previously fill the joining portion with magnetic powder and then coating the portion with a 2-cyanoacrylate based composition so as to fix adherends to each other, as described, for example, in Patent Literature 1.
On the other hand, as adhesive compositions having magnetism, various adhesive compositions have been conventionally proposed and used for the purposes of, for example, imparting magnetism to joining portions of electronic components and the like. For example, Patent Literature 2 discloses a ferromagnetic adhesive comprising an epoxy resin to which ferromagnetic powders such as Fe and Fe—Si are blended. Further, Patent Literature 3 discloses an adhesive composition which comprises two-part acrylic adhesives one part of which contains ferromagnetic powder such as iron powder. Further, Patent Literature 4 discloses a magnetic adhesive composed of at least one of a thermosetting silicone resin, an epoxy resin, a moisture-curable resin, an acrylic resin and an ultraviolet-curable resin, and a Mn—Zn ferrite magnetic powder.